Struts 2.5.2 HTTP Status 404 - There is no Action mapped for namespace [/] and action name [regist_A

使用Struts2.5.2   学习Action通配符时，出现错误：HTTP Status 404 - There is no Action mapped for namespace [/] and action name [regist_Action] associated with context path [/wildcard1].

在确保代码无误的情况下，用Struts2.3 JAR包代替后可正常使用，而Struts2.5不行，最后确定是Struts2.5.2 JAR本身的问题。

查看文档struts-2.5.2\docs\docs\action-configuration.html后找到问题所在。

首先，2.3版本中多了一个Strict DMI，当设置包属性strict-method-invocation="true" 时，Struts会拒绝一切不明确的方法属性包括通配符。（有点难翻译，具体看原文）

而2.5版本中的 Method Invocation(SMI)继承了2.3中的Strict DMI，属性strict-method-invocation被默认设置为true，所以才会出现这个错误。

解决方法：修改struts.xml，在准确添加method

method="{1}">

/WEB-INF/content/error.jsp
/WEB-INF/content/welcome.jsp
login,regist


/WEB-INF/content/{1}.jsp

附docs部分原文：

Strict DMI

In Struts 2.3, an option was added to restrict the methods that DMI can invoke. First, set the attribute strict-method-invocation="true" on your  element. This tells Struts to reject any method that is not explicitly allowed via either the method attribute (including wildcards) or the  tag. Then specify  as a comma-separated list of method names in your . (If you specify a method attribute for your action, you do not need to list it in .)

Note that you can specify  even without strict-method-invocation. This restricts access only for the specific actions that have .

Example struts.xml

xml version = "1.0" encoding = "UTF-8" ?>

    "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
    "http://struts.apache.org/dtds/struts-2.3.dtd">
< struts >

  < constant name = "struts.enable.DynamicMethodInvocation" value = "true" />

  < package name = "default" extends = "struts-default" strict-method-invocation = "true" >

    < action name = "index" class = "org.apache.struts2.examples.actions.Index" >
        < result name = "success" type = "redirectAction" >hello result >
    action >

    < action name = "hello" class = "org.apache.struts2.examples.actions.HelloAction" >
        < result name = "success" >/WEB-INF/content/hello.jsp result >
        < result name = "redisplay" type = "redirectAction" >hello result >
        < allowed-methods >add allowed-methods >
    action >

  package >
struts >

Strict Method Invocation

In Struts 2.5 the Strict DMI was extended and it's called Strict Method Invocation aka SMI. You can imagine that the DMI is a "border police", where SMI is a "tax police" and keeps eye on internals. With this version, SMI is enabled by default (strict-method-invocation attribute is set to true by default in struts-default package), you have option to disable it per package - there is no global switch to disable SMI for the whole application. To gain advantage of new configuration option please use the latest DTD definition:

Struts 2.5 DTD

xml version = "1.0" encoding = "UTF-8" ?>

        "-//Apache Software Foundation//DTD Struts Configuration 2.5//EN"
        "http://struts.apache.org/dtds/struts-2.5.dtd">
< struts >
...
struts >

SMI works in the following way:

•  / @AllowedMethods is defined per action - SMI works without switching it on but just for those actions (plus adding )
• SMI is enabled but no  / @AllowedMethods are defined - SMI works but only with 
• SMI is disabled - call to any action method is allowed that matches the default RegEx - ([A-Za-z0-9_$]*)

You can redefine the default RegEx by using a constant as follow 

When using wildcard mapping in actions' definitions SMI works in two ways:

• SMI is disabled - any wildcard will be substituted with the default RegEx, ie.:  will be translated into allowedMethod = "regex:perform([A-Za-z0-9_$]*)".
• SMI is enabled - no wildcard substitution will happen, you must strictly define which methods can be accessed by annotations or  tag.

You can configure SMI per  using  tag or via @AllowedMethod annotation plus using per  , see the examples below:

SMI via struts.xml

< package ...>
  ...
  < global-allowed-methods >execute,input,back,cancel,browse global-allowed-methods >
  ...

  < action name = "Bar" >
    < allowed-methods >foo,bar allowed-methods >
  action >

  ...
package >

SMI via annotation on action class level

@AllowedMethods ( "end" )
public class ClassLevelAllowedMethodsAction {
    public String execute() {
        return ...
    }
}

SMI via annotation on package level (in package-info.java)

@org .apache.struts2.convention.annotation.AllowedMethods({ "home" , "start" })
package org.apache.struts2.convention.actions.allowedmethods;

Allowed methods can be defined as:

• literals ie. in xml: execute,cancel or in annotation: {"execute", "cancel"}


• patterns when using with wildcard mapping, i.e 
• RegExs using regex: prefix, ie: execute,input,cancel,regex:user([A-Z]*)

Please be aware when using your own Configurationprovider that the logic to set allowed methods is defined in built-in providers - XmlConfigurationProvider and PackageBasedActionConfigBuilder - and you must replicate such logic in your code as by default only execute method is allowed, even when SMI is disabled.